Ultra-Wideband Monopole Antenna with Defected Ground for Millimeter-Wave Applications

An ultra-wideband millimeter-wave (mmWave) monopole antenna is presented. The antenna with a size of 10 × 10 × 0.508 mm3 operates between 20.8 and 46.4 GHz. It consists of a half-elliptic monopole patch with two slots and a defected ground plane with a triangularly cornered notch. The monopole is fed by a stepped impedance-matched transmission line. The evolution of the antenna is observed over four different patch and ground plane designs. Moreover, a parametric study is performed for controlling the return loss performance. The antenna is prototyped on Rogers RT/duroid 5880 laminate, and hereby, it is validated through measurements of return loss, radiation patterns, and peak gain. Based on the measurement, the antenna operates at the frequency range of 21.9–43.5 GHz (43.5 GHz is the limit of VNA). Moreover, the mmWave antenna is compared with the state of the art. It overperforms the others reported elsewhere. Hence, it is suitable for the mmWave applications, thanks to the ultra-wideband operation, simple geometry, and quasi-omnidirectional radiation.